Electrical apparatus



26, 1952 D. F. ALEXANDER ELECTRICAL APPARATUS Filed March 7, 1946 3 Sheets-Sheet l IIHHII INVEN TOR.

III III f BYM Aug. 26, 1 D. F. ALEXANDER ELECTRICAL APPARATUS 3 Sheets-Sheet 2 Filed March '7, 1946 MXMINVENTOR.

D. F. ALEXANDER ELECTRICAL APPARATUS 3 Sheets-Sheet 5 Filed March 7, 1946 I i I I I I I I I I I I I I l l I l I l I I F ma J /56 J i fifl /{//4I K INVENTOR MXM BYWM'% Patented Aug. 26, 1952 UNITED STATES PATENT OFFICE ELECTRICAL APPARATUS Donald F. Alexander, Oakwood, Ohio, assignor to General Motors Corporation, Dayton, Ohio, a

corporation of Delaware Application March- '7, 1946, Serial No. 6524515 11v Claims (01. 62--4) This invention relatesto: electrical apparatus:

nate light flicker in afcombination air condition ing and lighting system'such'as that-used on railway cars and similar-installations.

Still another object of'this invention: is to-provide a generatorsystem"inwhich one generator supplies 220 volts for the air conditioning apparatus and another generator supplies 120 volts for the lighting and ventilatingapp'aratus,

A further object of this inventionistoprovide an improved'arrangement'fforisupplying electrical energy from one railway. car: to another railway car for operating. emergency. lightinga-an'd .ventilating equipment.

More specificallyit is an objectisofi this inven tion to provide a system"'usingia single diesel. engine which operates one exciterand aof. alternators for supplying current at different voltages to the air conditioning, and lightingapparatus.

A further object of this invention is-to provide a simplified fieldcontrol arrangement.

Still another object of thisinventionis to provide a system in which arectifiermay be used for exciting the fields of two'alternators driven by acommon prime mover.

Further objects and advantages of thepresent invention will be apparentfrom the. following-dersoription, reference being. had to the accompanying drawings, wherein a preferred'fo'rm of the present invention isclearlyshowns In the drawings: 7

Fig. 1 is a diagrammatic'view showing a-raiP way car equipped witha system embodying featuresof my invention; a I I Fig. .21 is a diagrammatic view showing a preferredcircuit arrangement; and

Fig. 3 is a diagrammatic view showing a modified circuit in which the usual-exciter has been eliminated and a rectifier has been providedfor supplying the necessary field excitation.

For purposes of illustration, the combination lighting and air conditioning system has been shown applied to a-railway car whereas many features of my invention are-equally applicable to stationary installations such as may be used in theaters andofiice buildings.-

Referring now to Fig. lot the drawing, wherein a preferredembodimentof my invention has been shown, reference numeral 10' designates a conventional railway-car provided with'an air conditioning plenum chamber l2 located adjacent the one end of the car and within which a pairrof refrigerant evaporators 2'4 and 26 are mounted as shown. The refrigerating" system employs a multiple cylinder compressor adapted to be operated'at a constant speed. The

compressor M is provided with means I 6: for

rendering one or more of the cylinders inoperative when reduced capacity isdesired:- The cylinders may berenderediinoperative in anyof several well known ways such as by'liftingt or more of the discharge valves.

The compressed refrigerant is discharged into the condenser 2 llfromwhence the condensed re- Trigerant flows into the receiver .22.. .Liquid re- 30 frigerant is supplied-from: the; receiver' 2 2 to' the evaporator sections Hand-26 through the line 28. A conventional thermostatic expansion valve 39 controls the flowof liquid refrigerant to "the evaporator section 25 in accordance with well known practice. sion valve 32- controls the flow of refrigerant to A solenoid valve- 34 A similar thermostatic expanthe evaporator section 24. has been provided-in the liquidrefrigerant line leading to the valve'32 for shutting off the supply of refrigerantto the evaporator section 24' when it is desired tooperate the refrigeration system at a reduced'capacity.

The refrigerant vapor leaving the evaporator sections 24 andefifisisconveyedto. the compressor through the vapor line. 3'6as-shoWn.- The compressor. i driven .bya 220 volt alternating current motor 38. Themotorfiil'maybe directly oonnectedto the. compressor I l, or it ma drive the compressor through a belt means '46 as indicate'din Fig. 1'.

Each railway cari'is provided with a complete power'system which supplies all the necessary electrical energy for operating the refrigerating apparatus; car lights and all other electrical.

equipment. By providing such a separate power M of the type one 3 system on each railway car, the load on the head engine is Very materially reduced with the result that more cars can be used in a single train and better acceleration can be obtained. In the modification shown in Fig. 1 of th drawing, a diesel engine 50 has been provided for operating the dual alternators 52 and 53 and the exciter 54. Reference numerals 56 and 58 designate the engine starterand the magnetically con-trolled engine throttle, respectively.

The heat generated in the diesel engine may be dissipated by the engine radiator 60 or it may be dissipated by the heat exchange unit 62 located in the plenum chamber I2. The heat exchange unit 62 may be used for reheating the air during the cooling season and for supplying heat to the conditioned space during the heating season. A three-way valve 64 has been provided for controlling the flow of heating medium to the heat exchangers 60 and 62. In order to simplify this disclosure the valve 64 has been shown as a manually controlled valve, whereas it may be automatically controlled in response to either the temperature, the relative humidity, or a combination of both within the conditioned space.

The preferred electrical arrangement has been diagrammatically shown in Fig. 2 of the drawing, wherein reference numerals I and I2 designate the main direct current power lines from whence power is supplied to the various automatic controls to be described hereinafter. Reference numeral I4 designates a conventional storage battery which is connected across the lines 70 and I2 for supplying emergency direct current power when the exciter 54 is not in operation.

The dual alternators 52 and 53 are direct connected to the diesel engine 50 so as to be operated thereby whenever the engine 50 is in operation. The engine 50 is preferably a constant speed engine capable of operating the alternators at uniform speed irrespective of the load placed on the alternators. The alternator 52 is provided with a field coil I6 which is connected in circuit with the exciter 54 as shown. The alternator 53 is similarly provided with a field coil I8 which is connected in parallel circuit relationship with the field coil i6. Adjust able resistances 80 and 82 are provided for manually varying the resistances of the respective field circuits in accordance with well known practice. The flow of current to the field coils 16 and I8 is controlled by means of the constant current regulator 84 which comprises a carbon pile 86 and a solenoid 88 which is used for varying the resistance of the carbon pile 86 so as to maintain the flow of current through the regulator 84 substantially constant at all times.

The alternator 52 is provided with an armature 90 which supplies three phase, 60 cycle, 220 volt current to the power lines 92 for energizing the car heating elements 94, the compressor motor 38, the condenser fan motor 96 as well as any other heavy duty electrical equipment which it might be found desirable to have on the car. The flow of current to the electric heaters 94 is controlled by the switch 98 and the flow of current to the compressor motor 38 and the condenser fan motor 96 is controlled by the switch 100 arranged in the circuit as shown.

The alternator 53 is provided with an armature I02 which supplies 3 phase, 60 cycle, 110 volt power to the 110 volt power lines I04 which in turn supply power to the evaporator fan motor I06, the fluorescent car lights I08, and the car jumper connection IIO. A switch unit H2 is provided for disconnecting the 110 volt equipment from the alternator 53. This switch makes it possible to disconnect the armature I02 from the circuit when it is desired to energize the 110 volt equipment from a similar alternator provided on an adjacent car. The jumper connection 110 is intended to be used only in emergencies for connecting the 110 volt equipment on one car with the 110 volt equipment on an adjacent car so as to provide car lighting and air circulation on two adjacent cars from a single alternator when only one of the diesel engines is in operation. The blower motor I06 is controlled by the manual switch II4 and the lights are controlled by the manual switch II6.

. By virtue of the above described alternator arrangement, it becomes practical to provide a low voltage jumper connection for directly connecting the lights and blower motors from two separate cars to a single alternator without using any transformers. In the prior art systems using a single high votage alternator for supplying current to the heavy duty air conditioning apparatus and the lighting equipment, it is necessary to provide special voltage regulators for preventing light flicker when the heavy duty equipment is turned on, and it is also necessary to provide transformers for supplying volts to the lights, etc. Voltage regulators and transformers require frequent servicing by specially trained men and are not too dependable. Thus it is apparent that many service difiiculties may be eliminated by providing one high voltage alternator for supplying the heavy duty apparatus and by providing a separate low voltage alternator for supplying current to the lighting and generating circuits. Even though two alternators are provided, only one prime mover, one storage battery, and only one exciter need be provided when using the system disclosed herein.

The exciter 54 keeps the battery I4 charged and energizes the field windings I6 and I8 of the two alternators. It comprises the usual armature I20, field coil I22, and voltage regulator and reverse current relay I24 all of which function in their well known manner and need no further description.

A master control switch I30 controls the supply of power from the line I0 to the various control circuits as shown. In order to start the diesel engine, it is first necessary to close the switch I30 and then operate the push button I32 which is arranged'in series with the solenoid I34. Energizationof the solenoid I34 lifts the starting motor switch I36 and the throttle operating switch I38. Closing of the switch I36 directly energizes the heavy current or pull-in coil I40 and the voltage or holding coil I42 so as to initiate operation of the starting motor 56 in accordance with conventional practice. After the diesel engine 50 has been brought up to speed, the oil pressure within the diesel engine will cause closing of the oil pressure operated switch I44 with the result that the throttle solenoid I46 will remain energized even after the push button I32 has moved to the open position and the switches I36 and I38 have dropped into the open circuit position. Energizationof the voltagecoil I42 and the pull-in coil I40 causes closing of the switch I4I with the result that the pull-in coil. I40 will be short circuited and the switch I4I will be held closed merely by the holding coil I42.' A safety switch 5. I50 isprovided in, circuit with the throttle solenoid I46 and is adapted to be opened immediatelyin theevent that the diesel engine overheats. The relay I24 holds open the switch I35 at all times when the exciter and consequently the engine 50 are in operation.

The cooling and heating control circuits are controlled by the switch I52 arranged in series with the manually operated changeover switch I54. This latter switch is used to turn on either the heating equipment or the cooling jequipment depending on which form 'of air conditioning is required, The, switch I52 is under control' of of the, solenoid I62 which. in turn controls the switch SBJand the flow of current to the electric heater 94. The thermostat; I 501is adapted to close at a given temperature which indicates the need for heating:

When the change-over switch I54" is in its full lineposition, it connects the motor control thermostat I10 and the modulating thermostat I'I2-in circuit: The-thermostat H is designed to close when the temperature in the car first exceeds that temperature at which-the air conditioning apparatus should turn on. Closing of the thermostat I energizes the solenoid I14 which then closes the compressor motor control switch I00. The solenoidIM is also arranged to operate the time delay. switch I'I6' which is adapted to clos approximately. five seconds after the compressor motor 38- has been energized. The five second delay allows the compressor motor to come up to speed before the switch llfi'closes. A dashpot I80. has been provided for delaying the closing of theswitch I16. The spring connection IB2-has been provided so as to allow the switchI00 to close without waiting for. the, switchv III; to. move to its uppermost position.

The thermostat I12, is adapted] to close ata slightly higher temperature than the thermostat IIIJ and is arranged in serieswith the solenoid I84. Before thesolenoid -I8'4.can be energizedit is necessary that boththe-switch I76 and-,the-thermostat I'I2,be in their closed circuit position. When the solenoid I84isfirst energized, it moves. the switch I86into its upper-position, in which position the-circuit to the solenoidvalve 34isclosed. This causesthe valve to open so asto. allow the fiowof refrigeranttothe evaporator section 24, whereby both evaporator sections are effective to cool the air forthe space to be conditioned. Lifting ofthe switch [88} also deenergizes thev unloader I6 whereby. the compressor is operated at'full capacity, When the switch I86 returns to its lowermost position, the. refrigerant valve 34 shuts.,.off. the fiow of refrigerant to the one evaporator section and the unloaderx solenoid I5. becomes energized whereby the compressor is operated at=a reduced; capacity.

. Av slightlyv modified circuit. arrangement has.

been shown in Fig. 3. The system shown therein is substantially the same as; the system shown.

in Fig. 2 except. that a.-.rectifier 200 has been provided for, energizingthe fields ofithe-alternatorsinlieu of the direct current generator or exciter 54 sh'ownin Fig 2. The, same reference numerals. have-been. used to designate corresponding elements in Figs. 2 and 3 1 and unless.

otherwise indicated. the elements shown. in Fig. 3 function in the same manner asv the corresponding elements 1 shown in Fig. 2.

As indicated in Fig.3 of the drawing, a rectifier 200ha-s been providedifor supplyingdirectcurrent to the power lines '10, I2 during normal operation. of the diesel engine and the. alter-- nators driven thereby.- The. alternator 53 sup-- plies alternating current: to the rectifier 200 which rectifies the; current andysuppliesr efi currentto the rectifier: outpnta lines; 202; Since the rectifier 20.0 is :incapableof; supplying: power until after the; alternator-53 hasgstarted generating current, it is: necessarywto energize: the;

field of the alternator directly; from" the storage battery until the rectifier output is suflicient: to

properly excite the: fields of th valternators.

The switch 204' has been provided in the circuit asshown for directly connecting the fields I6 and "I0 of" the 1 alternators'52: and 53 across. the storagebattery. untilthe-output ofthe alternator '53. is sufficient to. supply the: rectifier with enough power to energize: the relay:- 208.

which is arranged acrosstheaoutput-lines12'02 of the rectifier; Energization of the-relayZIlIi causes closing of the. switch 208:

which, when fully energized; opens the'switches I35 and 204 and closesthe switches2l2 and'2I4.

Opening switch 204places-the carbon pile rheostat 2 I6 in series with the field windin'gsr'lli and "I8 of the alternators 52; andx53' respectively.

resistance 2I8 when'the solenoid I 14' closes the switch I00 leading to the -compressor motor- 33 and the condenser'fan 96. By virtue of this arrangement the'field excitation=of the alternator I8 is automatically adjusted to take care of the changein load-on the alternator -52.when the refrigeration equipment" is turned on;

A switch 224- has been provided for shorting out a portion of the'field'resistance 2I8 when the electric heaters 94 are turned on in response to a demand for electric heating. A switch 225 has been provided for disconnecting the alternator fields I6 and "when the diesel engineis not inoperation. manually operated switch or. it may be operated automatically to open the circuitinresponse to stopping of the dieselengine.

Closing of the,switch.2l'2"by;the solenoid 2I0 connects the outputof the rectifier 200 to the direct current power, lines; I0, I2 so as to -make it possible to charge 'the. storage. battery I4 from the rectifier. Closing. of the switch 2I4 energizesthe solenoid/22 6 which automatically closes theswitch II2 leading to thecar jumper H0, the fluorescent car; lights" Illa-and the evaporator blower I06. Byvirtue-of-thisswitching arrangement, it is apparentathat:the-alter nator. 53.v is .not called upon to.:supply':power.-' to the car lights, etc., until after th rectifier has The switch 208 is arranged inserieswith the solenoid 2III The switch, 225 may be a.

been supplied with enough power. to properly excite the fields of; the alternators."

The relay 210 operates much like a reverse currentrelay in that it is capable of holding the switches 2I2 and 2I 4 closed only so long as the rectifier'is supplying direct current to the lines 202. Thus; when the diesel engine and the alternators are stopped, the rectifier becomes ineffective to supply the necessary voltage required for properly energizing the relay 2m with the result'that the switches 212 and 214 open and the switches B5 and 204 close.

While the form of embodiment of the invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted, as may come within the scope of theclaims which follow.

What is claimed is as follows: I

1. In combination, a prime mover, a first generator includinga field circuit and an armature circuit, a second alternating current generator including a field circuit and an armature circuit, a first electric power consuming means, a second electric power consuming means, current rectifying means connected to the armature circuit of said second generator for supplying rectified current to the field circuits of said first and second generators, means for supplying current from said first generator tosaid first and second power consuming means, said field circuit of said first generator'including a resistance unit, first means for shorting a portion of said resistance unit, second means for shorting a portionof said resistance unit, means operable upon energization of said first power, consuming means controlling the first of said shorting means, and means responsive to energization of said second power consuming means-for controlling said second shorting means.

2. In combination a: first generator including a field circuit andv an armature circuit, a second alternating current generator including a field circuit and an armature circuit, electric power consuming means, electric lighting means, means for rectifying current supplied by one of said armature circuits, means for supplying said rectified current to said field circuits, means for supplying current from said first generator to said power consuming means, means for supplying current from said second generator to said lighting means, said field circuit of said first generator including a resistance unit, means for shorting a portion of said resistance unit, and means operable in response to energization of said power consuming means for controlling said shorting means. a

3. In combination, a power source, a first alternating current generator driven by said power source, a second alternating current generator driven by said power source, means for rectify-- ing current generated by one of said generators, said first and second alternating current generators comprising field coil means, and means for supplying current from said rectifying means to said field coil means, electrically energized means, means for supplying electrical energy to saidelectrically energized means from said first alternating current generator, electric lighting means, and means for supplying electrical energy to said electric lighting means from said second named alternating current generator whereby changes in load on said first named alternating current generator donot cause said electric lighting means to flicker. V

4. In combination, a prime mover, a first alter-v nating current. generator driven by said prime mover, a second alternating current generator driven by said prime movenmeans for rectifying current generated by one of said generators, said first and second named generators comprising field coil means, means for supplying said rectified current to said field coil means, electric power consuming means, means for supplying electrical energy to said power consuming means from said first named alternating currentzgenerator, electric lighting means,,and means for energizing said electric lightingmeans from said second named alternating current generator, whereby changes in load on said first named generator do not cause said electric lighting means to flicker. e

5. In combination, a prime mower, a first alternating current generator driven by said prime mover, a second alternating current generator driven by said prime mover, means for rectifying current generated by one of said generators, said first and second named generators comprising field coil means, means for supplying said rectified current to said field coil means, electric power consuming means, means for supplying electrical energy to said power consuming means from said first named alternating current generator, electric lighting means, means for energizing said electric lighting means from said second named alternating current generator, whereby changes in load on said first named generator do not cause said electric lighting means to flicker, storage battery means, means for connecting the out-put of said current rectifying means to said storage battery means, and means for energizing said field coil means from said storage battery when said rectifying means is ineffective to energize said field coil means.

6. In combination, a power source, a first generator driven by said power source, a second generator driven by said power source, a motor, means for supplying electrical energy to said motor from said first generator, electric lighting means, means for energizing said electric lighting means from said second generator whereby changes in load on said first generator do not cause the electric lights to flicker, means for starting and stopping said motor, said first and second generators comprising field coil means, a rectifier, means for connecting the out-put of one of said generators to said rectifier, means for supplying rectified current from said rectifier to said field coil means, resistance means for controlling the flow of current through said field coil means, and means for varying the fiow of current through said resistance means.

'7. In combination, a prime mover, a first alternating current generator driven by said prime mover, a second alternating current generator driven by said prime mover, means for rectifying current generated by one of said generators, said first and second named generators comprising field coil means, means for supplying said rectified current to said field coil means, electric power consuming means, means for supplying electrical energy to said power consuming means from said first named alternating current generator, electric lighting means, means for energizing said electric lighting means from said second named alternating current generator, whereby changes in load on said first named generator do not cause said electric lighting means to flicker, storage battery means, means for connecting said storage battery to the output of said rectifying means, and means for supplying current from said storage battery to said field coil means when said rectifying means is inefiective to energize said field coil means.

8. In combination, a power source, a first generator driven by said power source, a second generator driven said power source, a motor, means for supplying electrical energy to said motor from said first generator, electric lighting means, means for energizing said electric lighting means from said second generator whereby changes in load on said first generator do not cause the electric lights to flicker, means for starting and stopping said motor, said. first and second generators comprising field coil means, a rectifier, means for connecting the output of one of said generators to said rectifier, means for supplying rectified current from said rectifier to said field coil means, resistance means for controlling the flow of current through said field coil means, means for varying the flow of current through said resistance means, means for short circuiting said resistance means, and means responsive to the output of said rectifier for controlling said short circuiting means.

9. Air conditioning means for an enclosure including a multiple cylinder compressor, means for unloading at least one but not all of the cylinders, a two-position control means for said unloading means having a first position for unloading said one cylinder and a second position for loading said one cylinder, condensing and evaporating means operably connected to said compressor, means for flowing air for said enclosure in thermal exchange with said evaporating means, a first thermostatic control means responsive to a predetermined temperature within said enclosure for starting said compressor, a second higher temperature thermostatic control means for controlling said two-position control means to move it to unloading position at lower temperatures to unload said one cylinder under starting and light load condition and responsive to the higher temperature to move the two-position control means to the loading position.

10. In combination, a first alternating current generating means including a field circuit and an armature circuit, a second generating means including a field circuit and an alternating current armature circuit for generating alternating current and a direct current supply means, a single common power source for driving said first and second generating means, electric power consuming means connected to the armature circuit of said first generating means, said field circuits being connected in parallel circuit relationship, means for supplying direct current from said di- 10 rect current supply means in parallel circuit relationship to both of said field circuits, and a common constant current regulating means con nected in series with both of said field circuit-s and responsive to the flow of current from said direct current supply means to said field circuits for providing a substantially constant flow of current through both of said field circuits.

11. In combination, a first alternating current generating means including a field circuit and an armature circuit, a second generating means including a field circuit and an alternating current armature circuit for generating alternating current and a direct current supply means, a single common power source for driving said first and second generating means, electric power consuming means connected to the armature circuit of said first generating means, said field circuits being connected in parallel circuit relationship, means for supplying direct current from said direct current supply means in parallel circuit relationship to both of said field circuits, and a common constant current regulating means connected in series with both of said field circuits and responsive to the fiow of current from said direct current supply means to said field circuits for providing a substantially constant fiow of current through both of said field circuits, one of said field circuits being provided with an adjustable variable resistance for regulating its current flow.

DONALD F. ALEXANDER.

REFERENCES CITED The following references are of record in the file of this patent:

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